The present invention relates to a stack gripper, and more specifically, to a stack gripper which allows a regularly stacked box stack to be picked up and transported in a state in which the box stack is automatically arranged by pressing the box stack in horizontal and vertical directions.
Generally, a handler, a robot, a transfer machine, and the like include grippers with various structures to optimally grip objects to handle, transfer, and stack various articles, components, and so on, wherein the grippers are also referred to as a hand or an end effector.
Grippers are classified into mechanical grippers, vacuum grippers, and magnetic grippers depending on an operation method. Mechanical grippers grip an object by operating two to four fingers using a pneumatic, hydraulic, electrical, and spring operation.
Grippers should be designed with a structure in which they can perform efficiently and stably according to the properties of the object.
Particularly, a gripper for a pack handler is disclosed in Korean Registered Patent No. 10-0622664 (hereinafter, referred to as Prior-Art Document 1). The gripper for a pack handler includes a first rotary plate mounted on one side of a frame to rotate on first and second shafts arranged along a Y-axis line, a second rotary plate mounted on the other side of the frame to rotate on third and fourth shafts arranged along the Y-axis line, first and second fingers stretched out at a lower portion of the first rotary plate in parallel to each other to grip one side of a pack by rotating on a Z-axis line; third and fourth fingers stretched out at a lower portion of the second rotary plate in parallel to each other to grip the other side of the pack by rotating on the Z-axis line, a first operation device including a first air cylinder mounted at the front side of the frame and connected to the first rotary plate and making the first and second rotary plates interwork with each other by an operation of the first air cylinder, a second operation device including a second air cylinder mounted at an upper surface of the first rotary plate and making the first and second fingers interwork with each other by an operation of the second air cylinder, and a third operation device including a third air cylinder mounted on an upper surface of the second rotary plate and making the third and fourth fingers interwork with each other by an operation of the third air cylinder.
The gripper for a pack handler can efficiently and accurately stack packs in a box by minimizing strokes of fingers with a structure in which the fingers place the gripped packs by simultaneously rotating on a Y-axis line and a Z-axis line, and increase reliability by preventing a malfunction.
However, there is a disadvantage in that the gripper disclosed in Prior Art Document 1 is not applied to packing boxes manufactured one at a time due to the properties of the boxes.
That is, the packing boxes are manufactured one at a time, and boxes manufactured one at a time should be transported with the predetermined number of boxes stacked during transportation. Thus, the fingers of the gripper are in contact with both sides of the stacked boxes when the gripper in Prior Art Document 1 lifts the stacked boxes, and the boxes stacked on other sides with which fingers are not contact are in disorder and fall when the boxes are transported, and thus there is a disadvantage of difficulty of transportation.
The gripper for a handler described above is described in detail in the following Prior Art Document, the detailed description of which will be omitted.
(Patent Document 1) Korean Registered Patent No 10-0622664.